## SoLoud::EchoFilter

The echo filter in SoLoud is a very simple one. When the sound starts to
play, the echo filter allocates a buffer to contain the echo samples,
and loops through this until the sound ends.

The filter does not support changing of parameters on the fly, nor does
it take changing of relative play speed into account.

There are two parameters - delay and decay. Delay is the time in seconds
until the echo, and decay is multiplier for the echo. If the multiplier
is outside the [0..1[ range, the results are unpredictable.

    // Set up echo filter
    gEchoFilter.setParams(0.5f, 0.5f);  
    // Set the filter as the first filter of the bus
    gBus.setFilter(0, &gEchoFilter); 

### EchoFilter.setParams()

Set the parameters of the filter.

    gEchoFilter.setParams(0.5f, 0.5f);
    
Changing the parameters does not affect "live" sounds. If invalid parameters are
given, the function will return error.


### Live Parameter Access

All filters inherit the live parameter access functions.

- EchoFilter.getParamCount()
- EchoFilter.getParamName()
- EchoFilter.getParamType()
- EchoFilter.getParamMax()
- EchoFilter.getParamMin()
